A facile approach towards Wrinkle-Free transfer of 2D-MoS2 films via hydrophilic Si3N4 substrate

Abstract

Two-dimensional (2D) transition-metal dichalcogenides (TMDs) have been widely explored as next-generation semiconductor materials owing to their attractive electrical and optical properties. Currently, high-performance 2D-TMD-based electronic devices are obtained by transferring growth substrates onto target substrates. In practice, however, transfer-induced wrinkles and structural deformation on the target substrate pose a significant challenge. Herein, we successfully demonstrated a wrinkle-free transfer method that could facilely control the wrinkles of MoS2 thin films on hydrophilic Si3N4 substrates. Owing to the high wettability of the Si3N4 substrate, the residual water droplets between the MoS2 thin film and the target substrate were effectively removed, minimizing unexpected wrinkles and structural deformation. By simply adjusting the wetting properties of the target substrate, the device performance improved to a field-effect mobility of ∼ 0.756 cm2/(V·s), which is six times higher than that of the SiO2 substrate. Furthermore, the standard deviation of the electrical characteristics of the 50 2D-field-effect transistors was reduced by the Si3N4 substrate. In addition, the intrinsic characteristics of the MoS2 FET were evaluated by suppressing the effect of charge trapping through pulsed I-V measurements. Facilely-controlled wrinkles in MoS2 thin films can be used in various electronic devices, sensors, optoelectronic devices, and neuromorphic devices.